The United States of America requires that imported perishables be inspected for pests upon arrival to U.S. Ports of entry. If pests are detected in the perishables, then the U.S. inspector will determine if the in-coming perishables need to be fumigated before leaving the United States Custom""s quarantine areas. The reason for fumigating perishables is to eliminate any pests that the perishables may bring with them from foreign countries.
It is highly desirable that the amount of fumigant being released into our atmosphere during the fumigation of perishables be reduced. Today, there are two common methods of fumigating perishables. The first method requires tenting the cargo containers containing the perishables once the perishables have been taken to a site suitable for fumigation. The second method requires the taking of perishable in a container to a fixed site, unloading the perishable onto the fixed site, then carrying on the fumigation process and lastly, reloading the perishable to the cargo container that brought the perishable to the fixed site.
The first method of fumigation, the tenting, has the inherent disadvantage of having to fumigate a greater amount of cubic footage than would be required if the fumigation process would be carried out inside the cargo carrying container without the tenting. The fumigation of a greater amount of cubic footage in turn releases a greater amount of fumigant to our environment. The United States, through its statutes has stipulated that the amount of the fumigant, if the fumigant is methyl bromide, must be reduced by 50 percent by the year 2000. Another disadvantage that is associated with tenting is that the process can only be carried out when the weather is favorable, that is to say that if the wind is blowing to strong, the tenting should be avoided, for the chances of having the tented environment produce leaks is greatly enhanced. In the same line of thinking, The Plant Protection Quarantine Manual, PPQ 04/98-01 page 2.2.19, states that even in the best conditions, some gas will escape tented enclosures. Yet another disadvantage of tenting the cargo containers is that the sharp angles of the cargo container could tear the tarpaulins used to tent the containers, this would occur to either changes in weather or mishaps, such as the pulling of the tarpaulins due to a physical accident affecting the tented environment.
The second method of fumigation has the following disadvantages. First, by having to transport the perishables from location to location and the loading and unloading at each location, the life of the perishables are shortened due to the changes in temperature that the perishables experience, that is going from a refrigerated environment to one that is not refrigerated and back to a refrigerated environment. Second, it is not unusual to have mishaps in the loading and unloading of the perishables, the spillage of the perishables being fumigated. Thirdly, the amount of time and manpower required to carry out the process due to the loading and unloading is greatly increased, as opposed to just carrying out the fumigation process inside the cargo container.
Today, perishables are being fumigated with methyl bromide prior to being released from customs. Methyl bromide is a fumigant that is effective in eradicating pests that may be lying on perishables entering this country. Methyl bromide is a gas that is highly toxic and is detrimental to our environment, for this reason, the United States wants to phase out the practice of using methyl bromide in this type of fumigations. The problem that the U.S. encounters in phasing out this gas is that to date, methyl bromide is the most effective gas, workable, in eliminating pests from perishables coming into this country. Other chemicals may be used to eradicate pests, but to date methyl bromide has proven to create the least amount of toxic residue to the areas being fumigated, this in turn benefits the people applying the fumigant for they are not exposed to unsafe levels of fumigant. The reason for this is that methyl bromide disperses into the atmosphere at quicker rates than some of the other fumigants currently available for fumigations during the aeration process. The level of residue acceptable of methyl bromide gas after fumigations is five part per million. Information relevant to attempts to address these problems can be found in U.S. Pat. Nos. 6,047,496, 5,678,352, 5,662,865, 5,318,789 and 4,966.755.
U.S. Pat. Nos. 6,047,496 and 5,678,352 address the issue of reducing the amount of toxic agent being released into the environment by providing an improved structural fumigation process of using a non-flammable liquid cryogenic material which is vaporized to function as a carrier for the toxic agent. The patents do not address as how to minimize the area being fumigated nor do they suggest fumigating the perishables in a refrigerated environment.
U.S. Pat. No. 5,662,865 show an apparatus for fumigations with phosphine gas that form a circulatory loop that minimizes the disposal problems associated with phosphine gas. The patent is not geared toward the fumigation of perishables coming into this country, for phosphine gas requires a greater amount of time for the fumigation treatment of perishables to be effective.
U.S. Pat. No. 5,318,789 teaches how to package a commodity in a fumigation container, fumigating the commodity and shipping the commodity in the container. The patent is geared towards keeping fumigated commodities pest free in a sealed container after fumigation has occurred in this country. The patent requires the taking of the containers to chambers to carry out the fumigation. The present invention would conduct the fumigation in the refrigerated cargo container and thereby eliminate the dangers associated with mishaps, such as spills.
U.S. Pat. No. 4,966,755 describes an enclosure device, a tent, that would surround the item(s) being fumigated. The enclosure devise appears to be pieces of materials that are connected to each other so that fumigation can be undertaken inside of said pieces once connected. The device requires one to tent the item(s) to be fumigated.
For the forgoing reasons, there is a need for a method for fumigating perishables within an existing refrigerated cargo container that will reduce the amount of fumigant released into the atmosphere by at least thirty percent, if the fumigation process is carried out in a refrigerated cargo container, while at the same time prolonging the life of the perishables being fumigated. In addition, the method can be performed in weather conditions that would not permit the tenting method.
The present invention is directed to a method of reducing the amount of fumigant used during the fumigation of perishables and in which the method has the inherent advantage of prolonging the life of the perishable being fumigated. The method comprises of preparing an existing refrigerated cargo container that has already been transported to a site that meets the safety standards for fumigation of perishables. The method is conducted using an existing refrigerated cargo container that has the following physical attributes: two front and two rear drain holes, an air exchanger, a pair of doors that form a seal do to their construction and a refrigeration system. The method commences by first visually checking the outside of the refrigerated cargo container for any signs of damaged areas that may lead to leaks occurring. If damaged areas found, then sealing said damaged areas with a sealant, if possible, if damaged areas prove to be beyond repair, then do not proceed with the aforementioned method. Then placing at least one fan within the refrigerated container, this step can be done at this juncture or at any other juncture so long as one fan is connected to the gas introduction hose prior to the commencement of the fumigation process, the amount of fans required are dependant on the cubic footage of the container or the method of the invention being used. The next step would be to clear two of the drain holes in said refrigerated container. Through one of the drain holes cleared introduce a gas introduction hose, said gas introduction hose would be connected to one of the fans earlier introduced or to the fan earlier introduced, the fan would be positioned to blow the fumigant toward the front or the rear of the refrigerated container so that the fumigant introduced into the container can be dispersed within. Through the other drain hole cleared introduce reading lines and electrical lines for powering the fans or fan within the refrigerated container. The reading lines should be placed in the container according to the placement required by the PPQ manual or any other governmental guidelines for fumigations intact at the time of the fumigation process. After introducing the gas introduction hose, the reading lines and the electrical lines through the above drain holes seal the drain holes with any available commercial sealant that would prevent fumigant leakage. Then, plug the drain holes not cleared with a plugging means that would prevent fumigant leakage from the drain holes not cleared. Prior to conducting the fumigation or any other type of pressure tests, close the air exchanger of the refrigerated container. Then check the temperature of the perishable to be fumigated and determining the dosage of fumigant to be used during the fumigation process. Then, close and secure the doors of said refrigerated cargo container and then commence the fumigation process by releasing the fumigant through the gas introduction hose into said container. While releasing the fumigant into the container check the outside of said container, with a gas or halide detector, for any leaks of the fumigant being used. If leaks are discovered, then seal the areas found to have leaks with any available commercial sealant that seals leaks. After sealing the areas found to have leaks re-check the areas found to have leaks. If leaks are controlled to a satisfactory level, then conduct the fumigation process in the manner and for the period required by the U.S.D.A. or any other governmental agency guidelines for fumigations for the perishables being fumigated. Lastly, aerate the perishables for the required amount of time needed to clear the container of the fumigant. The refrigerated cargo container will not be completely cleared of the fumigant, the guidelines will instruct the fumigators as to how many part per million are required to establish that the fumigant has been aerated to a safe level before the perishables can be released. If for any reason gas leaks cannot be corrected during the fumigation process, then tent the refrigerated cargo container and conduct the fumigation process using the process described in the PPQ manual for fumigation of perishables.
In another embodiment of the invention, the rear drain holes would be used to introduce the gas introduction hose, reading lines and electrical lines and then the rear drain holes would be sealed to prevent gas leakage. The front drain holes would be plugged using any plugging means. If for any reason the rear drain holes cannot be cleared then clear the front drain holes and introduce the gas introduction hose, reading lines and electrical lines through the front drain holes and then the front drain holes would be sealed to prevent gas leakage, then plug the rear drain holes. It is foreseeable that one front drain hole and one rear drain hole may have to be cleared and the remaining drain holes plugged, and that the gas introduction hose and related lines introduced through the cleared drain holes and that said cleared drain holes would then have to be sealed to prevent gas leakage.
In yet another embodiment of the invention, the gas introduction hose, the reading lines and the electrical lines would be introduced through the air exchanger. Then the air exchanger would be sealed using a commercial sealant. All of the drain holes of the refrigerated cargo container would be plugged using plugs or sealant. The fumigation method would be carried out using the same method as above, incorporating the aforementioned steps into the fumigation method.
In another embodiment of the invention, it is foreseeable that a refrigerated cargo container will not have an air exchanger, if this is the case, then the step of closing the air exchanger in the above procedures would be eliminated. The process would be conducted exactly as above, except for the aforementioned step of closing the air exchanger.
In a further embodiment of the invention, the above procedure would be carried out while the refrigeration system of the refrigerated cargo container is running. This embodiment would eliminate the need of extra fans beside the fan required to introduce the fumigant into the refrigerated cargo container. The fan would serve to circulate the fumigant evenly within the cargo container and would prolong the life of the perishable being fumigated.
Another embodiment of the invention would add the further step of conducting a pressure test of said container prior to the commencement of the fumigation process.
Accordingly, it is a principle object of the invention to reduce the amount of fumigant required to fumigate incoming perishables. Because less fumigant is used during the fumigation process, less fumigant is released during the aeration step of the fumigation process, thereby reducing the harm that the fumigant does to our environment.
It is another object of the invention to prolong the life of the perishable being fumigated, this is accomplished by maintaining the perishable refrigerated during the refrigeration process and by exposing the perishable to less fumigant during the initial introduction of the fumigant into the refrigerated cargo container.
It is another object of the invention to reduce spillage associated with having to move a perishable from a cargo container to a fumigation site back onto a cargo container.
Yet another object of the invention is that it allows the perishable to be processed through the custom""s quarantine areas at a quicker pace than would be accomplished if having to load and unload the perishables at the fumigation sites or if having to tent the containers carrying the perishables.
Another object of the invention is that the fumigation process can be carried out under weather conditions that would not otherwise permit the fumigation process to be carried out under, such as windy conditions.
These and other objects of the present invention will become readily apparent upon further review of the following specifications and drawings.